Catalyst for synthetic-methanol production



PatentedApr. 26 1927. I

UNITED ST TES PATENT OFFICE.

JOHN (J. woonaorr AND enovnn BLOOMFIELD, or 'rnnan nan'rn, INDIANA, AB-

sreNoBs r commncrar. SOLVENTS CORPORATION, or 'rnnnn naorn, INDIANA,

A. CORPORATION OF MARYLAND.

CATALYST FOB SYNTHETIC-METHANOL PRODUCTION.

30 Drawing. Original application filed May 28, 1926, Serial 1%. 111,884.Divided and this application filed September 25, 1926. Serial No.137,810.

, Our invention relates to the production of methanol by the highpressure catalytic combination of oxides of carbon with hydrogen, andpertains more directly to the 5 preparation and employment of improvedcatalysts in the process.

Methanol maybe produced by combmmg oxides of carbon with hydrogen in thepresence of a suitable catalyst at elevated temperature and pressure.Carbon monoxide, carbon dioxide, and mixtures of the two oxides may beemployed, these substances reacting with hydrogen according to thefollowing equations Carbon monoxide-00 2H,: QH OH Carbon dioxide-CO,3H,?OI1,0H H O It is observed that when carbon dioxide is the oxideemployed, one molecule of water is formed for every molecule of methanolproduced. On the other hand when pure carbon monoxide is used,theoretically there is nothing roduced by the reaction but methanol.ctually in practice pure carbon -""monoxide and pure carbon dioxide areboth diflicult to obtain economically, so that the methanol synthesisiscarried out by reacting a mixture of carbon monoxide and carbondioxide with hydrogen.

methanol there are, in the methanol synthesis, undesirableside-reactions which cut down the yield of the desired product. The

principal side reaction which. may occur is the formation of methane,which is illustrated below:

carbon In addition to the reactions producing.

yd og I temperature above C. there is nearly always produced somereaction between the gaseous components. The extent of this reactiondepends to some degree on space velocity, temperature, and pressure, butthe fact remains that under the conditions outllned, carbon oxides andhydrogen react to some extent in all cases.

The substances formed by such a process depend both as to identity andas to amount, almost entirely on the nature and activity of thecatalytic substance present. The methanol catalysts proposed in the pasthave been of two princi a1 types :-i. e.-

1. Mixtures of nely div1ded metals, or, what is equivalent, mixtures ofeasily reducible metal oxides;

2. Mixtures of oxides of metals non-reducible, or diflicultly reducibleunder the conditions of the methanol synthesis.

In the past, also, one class of easily reducible metal oxides, that isthe oxides-of 1ron, nickel, and cobalt have been described as absolutelyworthless for the production of methanol catalysts since these metalsunder normal conditions prevent the formation of methanol, the reactionproducing only methane.

We have discovered a new typeof methanol catalyst which produces ahigher yield of methanol than those formerly employed in the art, and atthe same time produces a very pure methanol, uncontaminated bybyroducts. An additional advantage accrumg from the use of our catalystsis that the formation of methane in the process-with the consequentdestruction of valuable hydrogen-is practically eliminated.

We have now discovered a new type of valuable methanol catalyst whichcomprises three main elements-i. e. v

(1) One or more non-reducible metal 95 oxides such as zinc, magnezium,cadmium, chromium, "vanadium, tungsten, etc.

(2) One or more easily reducible metal oxides such as copper, silver,iron, nickel,

cobalt, etc.;

(3) A metallic-halide,

It will be observed that'in our'improved catalyst we may employsubstances normally deleterious to the methanol reaction namely themethanatin nickelforrcobaltr Inrour mproved catalyst compositions thesenormally deleterious substances serve advantageously, apparentlyexerting only a normal hydrogenating catalytic action productive ofmethanol. Or we may employ easily reducible oxides such as those ofcopper or silver which are already known in the art as advantageouscomponents of certain methanol catalysts. In these cases however, our imroved catalysts containing halides produce ar better results than thoseknown in the art for otherwise identical catalyst mixtures.

The precise method by which the metallic halides produce the lmprovementis not known to us. At least three theories may be used to account forthe phenomenonnamely (1) The metallic halide acts as an ordinarypromoter in increasing catalyst activit (2 The metallic halide interactswith other metallic oxides present in the catalyst to produceoxychloride compounds which, in turn, either serve as catalystpromoters, or may so modify the purely physical state of the mass as toproduce a more active catalyst;

(3) The metallic halide may be reduced by the high pressure contact withhydrogen and carbon oxides during the commencement of its use as acatalyst and the resultant-finely divided metal may increase thevcatalyst activity, or alternatively, the metallic halide may first reactwith some other metal producing the halide thereof, which may be reducedin the same manner.

However, the precise explanation for the improved result attained by theaddition of metallic halides to methanol catalysts is not known andforms no part of our invention.

To produce our improved catalysts it is not necessary that the amount ofmetallic halide added bear any exact weight relation to the remainingconstituents of the catalyst, though the amount of halide added shouldpreferably be less than one chemical equivalent of the amount ofprincipal metallic oxide resent in the catalyst.

As illustrative of our invention we will cite a number of specificcatalysts. In order to indicate the comparative 'efiicacy of thesecatalysts in methanol production we have selected a standard set ofcondition of use as follows. The reported yields of condensate from themethanol reaction by use of the following catalysts is based on theeffect produced when a as mixture comprising 8% carbon dioxi e, 3% ofcarbon monoxide and 89% hydrogen is passed through 1 liter of catalystgranules at a space velocity of 75,000-100,000, at a pressure of 2000ounds, andat a temperature of 340-400 In selecting a standard set ofconditions it is ourintention only to thus display the catalyst efficacyand by no means to limit the scope of our invention. Modification of theconditions of the reaction will, of course, modify the results, but theresults will always be proportionate to the catalyst em loyed.

or example, an increased space velocity produces an increased hourlyyield and an increase in operating pressure has the same effect.Likewise the use of pure carbon monoxide as distinguished from carbondioxide or a mixture of the two results in an increased methanolpercentage in the condensate, and, since carbon monoxide seems to reactmore readily, an increased condensate volume.

Ewamle I. 8 kilograms of chromic nitrate Or(NO QQH O) and 1.5 kilogramsof nickel nitrate (Ni (NO ),.6H,O)

I 1 liter, which analyzes about 35% methanol.

Emample H. 2250 grams of nickel nitrate (Ni(NO .6H O) are dissolved in250 liters of water and the solution is heated to 95 C. 7 500 zinc oxideis then added with stirring. To this solution there is added suflicientammonium hydroxide to recipitate the nickel as nickel h drate. T eprecipitated mass is recovere by decantation and filtration, isl washed,dried, and broken up into granu es.

To this mass is added a solution containin 740 grams of zinc chlorideand the mass is again dried. v

The hourly yield of condensate is about 1 liter and contains about 30%of methanol.

If the amount of zinc chloride used is doubled, the hourly condensatewill be increased to about.2.5 liters and the percentage of methanolwill be increased to a out 56%.

Substitution of chemically equivalent llO ams of and zinc oxide.

ken up into granules and is then moistened quantities .of magnesiumchloride or zinc bromide for the zinc chloride produces Sll'Illlarresults.

are dissolved in 5 liters of water. 2.5 kilograms of zinc oxide is addedwith stirring and the mass is heated to dryness and is then furtherheated till no more nitric oxide fumes are given oil, whereby themixture is transformed to chromic oxide, nickel oxide,

The resultant mass is browith a solution containing 450 grams of zincchloride. The granules are again dried 1 and are ready for use. Ifdesired, 450 grams of dextrin or a similar agglutinating agent maybeadded with the zinc chloride, whereby firmer granules are obtainedondrying.

The hourly 2.5 lltBPSCOIltitll'llllg about 58% methanol.

E mample IV.

'1. A methanol catalyst initially comprisield of condensate is about.

ing a plurality of diflicultly reducible metal oxides. nickel oxide, anda metallic halied.

2. A methanol catalyst initially com rising a diificultly reduciblemetal oxide, nickel oxide, and a metallic halide.

3. Amethanol catalyst initially comprising zinc oxide, chrom1umoxide,.nickel ox-- ide, and a metallic halide.

4.. A methanol catalyst initially comprising zinc oxide, nickel oxide,and a metallic halide.

5. A methanol catalyst initially comprisin}; zinc oxide, chromium oxide,nickel oxide, and zinc chloride.

6. A methanol catalyst initially comprising zinc oxide, nickel oxide,and zinc chloride.

7. A process for the production of synthetic methanol which comprisespassing a mixture of hydrogen and carbon oxides at a pressure in excessof atmospheres and at a temperature of 350-450 C. over a catalystinitially comprising a plurality of diflicultly, reducible metal oxides,nickel oxide, and a metallic halide.

8. A process for the production of synthetic methanol which comprisespassing a mixture of hydrogen and carbon oxides at a pressure in excessof 50 atmospheres, and at a temperature of 350450 C. over a catalystinitially comprising a diflicultly re ducible metal oxide; nickel oxideand a catalyst initially comprising zinc oxide,

chromium oxide, nickel oxide, and zinc chloride. In testimony whereofweafiix our signatures.

- JOHN G. WOODRUFF.

GROVER BLOOMFIELD.

